Receiving coil for train communication apparatus



Sept. 2, 1947. E. w. BREISCH RECEIVING COIL FOR TRAIN COMMUNICATIONAPPARATUS Filed Jan. 25, 1946 2 Sheets-Sheet 1 INVENIOR lbga W 519690/2.

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HIS ATTORNEY P 1947. E. w. BREISCH I 2,426,724

RECEIVING COIL FOR TRAIN COMMUNICATION APPARATUS Filed Jan. 25, 1946 2Sheets-Sheet 2 INVENTOR v Edgar W 51 6 6966 BY avzhfll zu H19 A TTORNE YPatented Sept. 2, 1947 RECEIVING COIL FOR TRAIN COMMUNICA- TIONAPPARATUS Edgar W. Breisch, Edgewood, Pa., assignor to The Union Switch& Signal Company, Swissvale, Pa., a corporation of PennsylvaniaApplication January 25, 1946, Serial No. 643,418

9 Claims. 1

My invention relates to receiving coils for train communicationapparatus, and more particular- 1y to coils mounted on a vehicle of arailway train for picking up energy inductively from trackwayconductors.

In railway train communication apparatus of the carrier inductive typeenergy is picked up on a train by means of a coil or an inductor mountedon the train in inductive relation to the rails and conductorsparalleling the rails. These coils are subjected to' abuse and severeoperating conditions and are exposed to all kinds of weather.Furthermore, these coils are generally air core coils of relativelylarge cores and possess definite characteristics due to the character ofthe service and such coil characteristics must be maintained unvaried toprovide efficient and reliable operation.

Accordingly, a feature of my invention is the provision of an improvedreceiving coil for train communication apparatus.

Another feature of my invention is the provision of a receiving coil ofsimple, rugged and economical construction which can be readily tuned,and having a housing that does not deflect the magnetic lines fromthreading the winding.

A further feature of the invention is the provision of a" receiving coilof the type here involved incorporating novel means to adequatelyterminal a coaxial cable at the receiving coil lead wires.

Other features, objects and advantages of my invention will appear asthe specification progresses.

To attain the foregoing features, objects and advantages of myinvention, I provide a circular shell of identical halves with adjoiningsurfaces falling along the central vertical plane. These two half shellsare of molded non-magnetic material and have a diameter predetermined toenclose the winding of the coil. The two half shells also are of a depthsuch that when joined together they form a compartment of a lengthsufficient to enclose the predetermined length of winding. A rim ismolded on each half shell to receive a group of screws spaced. along therim to secure the half shells together with adjoining surfaces forming aweathertight seal. To obtain a perfect seal an annular groove is moldedin the joining surfaces and a suitable gasket fitted into the groove.

A winding of a diameter and number of turns predetermined according tothe associated communication apparatus is wound on a tube of nonmagneticlnsulating material and the tube is mounted in the compartment of theshell by the ends of the tube fitting into annular grooves molded one ineach half shell. A lug is molded to each half shell so that when the twohalves are assembled a suitable outer surface is formed to which thereis attached a junction box, a

groove being molded in the lug to provide an opening from the outersurface to the compartment through which lead wires may be drawn. Thisjunction box is provided with terminal posts to which the lead wires maybe connected to the outside circuit connections and the junction box isformed with a surface that fits the outer surface of the lug so that thejunction box may be attached to the shell with a weathertight seal.

This lug formed on the shell is proportioned to provide surfaces towhich mounting brackets can be secured, two brackets being located, one

on each side of the box, and provided with means for attaching theentire assembled receiving coil to brackets mounted on the vehicl onwhich the coil is to be located.

The mounting brackets are preferably heavy steel U-shaped brackets whichstraddle the molded surfaces of the half shells on each side of thejunction box and are drilled in the base of the bracket to be bolted tobrackets mounted on the vehicle on which the coil is to be located. Inthis way strains on the molded shell are minimized and failure of theshell is avoided.

The number of turns and size of wire of the winding are preferablypreselected to permit the coil to be tuned by the use of a coaxial cableof a given length. However, in order to compensate for variations ofcable capacitance, a small winding wound on a small diameter tube may beprovided and held in place in the compartment of the shell by annulargrooves formed in the half shells. A powdered iron core may also bedisposed inside of this small winding in a manner that it can beadjusted as to its position inside the winding from outside of the shellby two screws of non-magnetic materialwhich thread through hubs of thehalf shells. These screws thus serve to position the iron core from theoutside of the 'shell by backing off one screw and tightening up on theother, the iron core being locked in any desired position.

I shall describe one form of receiving coil embodying my invention, andshall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a side elevational view showingone form of a receiving coil embodying my invention, the cover of thejunction box being removed. Fig. 2 is an end 3 view of the coil of Fig.1, and Fig. 3 is a sectional view taken on the line TIL-III of Fig, 1.

In each of the three views like reference characters designate similarparts.

Referring to the drawings, the reference character HS designates a shellof a receiving coil. The shell HS is of any suitable non-magneticmaterial and preferably it is of a molded material and a phenolicmaterial may be used. This, shell is made up of two identical halve land ll, which when placed together Joint along a center vertical plane.In this way the shell can be made from a single mold of relativelysimple construction. The half shells l0 and ii are of a diameterpredetermined according to the receiving coil required for the specificequipment with which the coil is to be associated. Also the half shellsare of a depth predetermined by the required length of the coil. Eachhalf shell 10 and I l is formed with a Joining face 9 of a rim 8, andthe two halves are assembled with the faces 9 Joining and boltedtogether by a group of brass machine screws i2 spaced alongthe rim 5.Although the joining faces 8 of the two half shells are smooth and leveleither as molded or by subsequent grinding making it possible to providea watertight assembly by a suitable cement, a further precaution istaken to obtain a perfect seal by molding an annular groove ii in theface 9 of the half shells and fitting a rubber gasket l4 into thegroove. When the two halves are joined together the gasket I4 issuppressed to completely fill the opening made by the two matchedgrooves The actual receiving coil consists of a winding l5 wound onatube IS, the tube I5 being of any suitable non-magnetic material andpreferably it is of an insulation material. The winding 15 is made of apreselected number of turns symmetrically wound on the tube. Thediameter of this winding and the size of wire and the number of turnsare preselected as required for proper operation with the associatedapparatus. The tube i6 is held in place in the compartment of the shellby means of annular grooves i1 formed in the half shells. To avoid anyloosening of the tube after the shell is assembled, a waxed twine 40 isinserted in at least one of the grooves H. The ends of the winding l5are connected to lead wires l8 and is which are brought into a junctionbox to be described later.

A lug 42 is molded to the lower portion of each half shell and when thetwo halves are assembled an outer surface 43 is formed and which surfaceis connected to the compartment of the shell by an opening 44 formed bygrooves molded in the lugs 42.

A junction box 2| of non-magnetic material such as cast aluminum isattached to the outer surface 43 by cap screws 22, a gasket beinginterposed between the box and the surface 43 to form an airtight andwatertight seal. Terminal posts 20 of standard design are mounted in thejunction box 2| on a suitable insulation base. secured to the junctionbox. The junction box 2| is also formed wtih a conduit or pipe opening24, through which outside conductors or cables can be brought into theJunction box and connected to the terminal post 20 for connection to thelead wires from the winding. The box 2! is provided with a cover 25which can be unscrewed to provide access to the terminal posts 20 formaking circuit connections.

An important factor in the construction of the receiving coil is theprovision of integral U -shaped metal mounting brackets 26 and 21. Thesetwo brackets are alike and are bolted to a section of the lug 42 bymeans of bolts 28, the two brackets being located one on each side ofthe Junction box 2|. Each of the brackets 26 and 21 is drilled at 29 forbolting the receiving coil to brackets attached to the roof or otherportion of the car or locomotive on which the receiving coil is to bemounted. The bolts 28 for securin the brackets to the shell also serveas an aid in clamping the two half shells I0 and II together. It is tobe pointed out that if the coil shell is bolted directly against themounting brackets on the car or locomotive, such mounting brackets arelarge and stiff and may not be properly aligned, and the molded shell ofthe coil may be put under a strain which would result in prematurefailure of the shell. When the shell is bolted to the U brackets 26 and21 and these brackets in turn are bolted to the vehicle bracket, thedanger of strain bein set up in the shell of the receiving coil isminimized.

A receiving coil of the form here provided can be tuned by using arequired capacitor, such as a capacitor 45 connected to the coil at theterminals 20 of the junction box, or the receiving coil may be properlytuned when relatively high frequency carriers are used by a properlength of coaxial cable for connecting the coil to the associatedequipment, such cable having an inherent capacitance needed to tune thecoil at the frequency of the carrier used. I have found that a coaxialcable of approximately 55 feet in length will tune a suitable receivingcoil when a carrier of the frequency of 88 kc. is used.

In order to compensate for variations of cable capacitance, a smalldiameter coil or winding may be included in the receiving coil. Such anadjusting coil includes a winding 30 wound on an insulation tube 3|which is held by annular grooves 32 molded in the half shells III andII. The ends of the winding 30 are connected through lead wires 33 and34 to selected terminals of the junction box 2|. A powdered iron core 35is inserted inside of the winding 30 to vary the inductance thereof bychanging the position of the core 35. External adjustment of theposition of the core 35 is effected through two screws 35 and 31 ofnon-magnetic material threaded to engage with threads molded in the hubof the half'shells l0 and II. By backing off screw 36 and tighteningscrew 31 or vice versa, the core may be moved to any position within thewinding 30 and locked in that position. Molded nuts 38 and 39 screw ontothe screws 36 and 31, respectively, to seal against entry of moistureand to lock the screws against accidental movement while the receivingcoil is in service.

It is apparent that the adjusting coil 30 and the associated structurecan be omitted when this added means for tuning the coil is notrequired.

A receiving coil such as here disclosed has the advantages of being ofsimple and economical construction, it is rugged to withstand abuse, itis sealed against weather conditions affecting the winding itself, thewinding can be readily tuned either by capacitance housed in theassociated junction box, or by proper length of connecting cable, or byan additional winding enclosed within the housing of the coil itself,and the special U-shaped brackets for mounting the coil assure thatstrains in the molded shell will not be set up when the receiving coilis mounted on the locomotive or car of a train.

Although Ihave herein shown and described but one form of receivingcoils for train communication apparatus embodying my invention, it isunderstood that various changes and modifications may be made thereinwithin the scope of the appended claims without departing from thespirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In receiving coils for inductively picking up communicationenergy,-the combination comprising, two molded non-magnetic shellsprovided with a joining surface for the twoshells to be assembled with aweathertight fit, said shells shaped to form a compartment when saidshells are assembled, a winding wound on a non-magnetic tubeproportioned to be housed in said compartment, each said shell moldedwith a groove into which the ends of said tube fit to position thewinding in said compartment, a projection molded on said shells to forman outer surface when the shells are assembled, a groove formed in saidprojection to provide an opening from said compartment to said outersurface, and a junction box attached to said outer surface and providedwith terminal posts for connection of lead wires of said winding broughtout through said opening.

2. In receiving coils for inductively picking up communication energy,the combination comprising, two identical molded non-magnetic halfshells provided with a joining surface for the two half shells to beassembled with a weathertight fit, said half shells shaped to form acompartment when said half shells are assembled, a winding wound on anon-magnetic tube proportioned to be housed in said compartment, eachsaid half shell molded witha groove into which the ends of said tube fitto position the winding in said compartment, a projection molded on saidhalf shells to form an outer surface when the halves are assembled, agroove formed in said projection to provide an opening from saidcompartment to said outer surface, a non-magnetic junction box attachedto said outer surface and provided with terminal posts for connection oflead wires of said winding brought out through said opening, and twometallic U-shaped mounting brackets to straddle surfaces formed on theoutside of said half shells and bolted thereto to mount, the receivingcoil.

3. In receiving coils for inductively picking up communication energy,the combination comprising, two identical molded non-magnetic halfshells provided with joining surface for the two half shells to beassembled with a weathertight fit, said half shells shaped to form acompartment when said half shells are assembled, a winding wound on anon-magnetic tube proportioned to be housed in said compartment, eachsaid half shell molded with a groove into which the ends of said tubefit to position the winding in said compartment, a projection molded onsaid half shells to form an outer surface when the halves are assembled,a groove formed in said projection to provide an opening from saidcompartment to said outer surface, a non-magnetic junction box attachedto said outer surface and provided with terminal posts for connection oflead wires of said winding brought out through said opening, saidprojection formed to provide two mounting surfaces one on each of saidouter surfaces, and two U-shaped metal mounting brackets one bolted toeach of said mounting surfaces for mounting said coil without strains tothe assembled half shells.

4. In a receiving coil for train communication apparatus, thecombination comprising, a circular shell of two identical parts ofmolded nonmagnetic material each said part having a preselected depthand a mating surface to form a compartment of preselected diameter anddepth when the parts are assembled with their mating surfaces engaging,a rim molded on said parts to assemble the parts with a weathertightjoint of said mating surfaces by screws spaced around said rim, awinding wound on a cylindrical nonmagnetic tube of a diameter and lengthpredetermined by the diameter and depth of said compartment, an annulargroove molded in each of said parts to receive the ends of said tube toposition said winding, said parts molded with a lug which is formed withan outer surface and a bolted to each of said mounting surfaces to mount1 the receiving coil with strains to said molded shell avoided.

5. In a receiving coil for train communication apparatus, thecombination comprising, a winding wound on a cylindrical tube ofinsulating material, an annular shell of two identical parts of moldednon-magnetic material having joining surfaces falling along the centralvertical plane of the shell and'a rim for assembling the two parts witha weathertight joint by a group of screws located in the rim, saidassembled two parts forming a compartment for housing said winding, eachof said parts molded with an annular groove to receive the ends of saidtube to position the winding, a lug molded on each of said parts andformed with a, groove and an outer surface to provide a junction boxsurface connected to the compartment by an opening through theassociated grooves when the parts are assembled, a junction box attachedto said junction box surface and provided with terminal posts toterminal lead wires of the winding brought out through said opening,said lugs formed with two molded surfaces one on each side of saidjunction box surface, and two U-shaDed brackets to straddle the mountingsurfaces formed by the parts assembled and bolted thereto to aid inclamping the parts together and to mount the shell without strains tothe shell.

6. In a receiving coil for train communication apparatus, thecombination comprising, a winding wound on a cylindrical tube ofinsulating material, a circular shell of two identical parts of moldednon-magnetic material having joining surfaces falling along the centralvertical plane of the shell and a rim for assembling the two parts witha weathertight joint by a group of screws located in the rim, saidassembled two parts forming a compartment for housing said winding, eachof said parts molded with an annular groove to receive the ends of saidtube to position the winding, 9. lug molded on each of said parts andformed with a groove and an outer surface to provide a junction boxsurface connected to the compartment by an opening through theassociated grooves when the parts are assembled, a junction box attachedto said junction box surface and provided with terminal posts toterminal lead wires of the winding brought out through said opening,another winding wound on another insulation tube-housed in saidcompartment, the last mentioned tube of a small diameter to go inside ofthe first mentioned tube and positioned in the compartment by otherannular grooves molded in each of said parts to receive the ends of saidlast mentioned tube, and the last mentioned winding having lead wiresterminaled at posts of said junction box for connection as required fortuning said first mentioned winding.

7. In a receiving coil for train communication apparatus, thecombination comprising, a main winding mounted on an insulation tube ofrelatively large diameter, an auxiliary winding mounted on an insulationtube of relatively small diameter, an annular shell of two identicalparts of molded non-magnetic material having joining surfaces fallingalong the central vertical plane for assembling the two parts by screwsalong the outer rim of the parts, said assembled shell forming acompartment to house said windings concentrically through grooves moldedin said parts to receive the ends of said tubes, an iron core slidablewithin said smaller tube, two non-magnetic screws threaded in hubs ofsaid parts t ngage opposite ends of the iron core to adjustably positionthe core in the smaller tube, and an opening formed in said shell tobring out lead wires from said windings whereby said windings can beconnected to variably tune the main winding according to the setting ofsaid iron core.

8. In a receiving coil for train communication apparatus, thecombination comprising, a main winding mounted on an insulation tube ofrelatively large diameter, an auxiliary winding mounted on an insulationtube of relatively small diameter, a circular shell of two identicalparts of molded non-magnetic material having joining surfaces fallingalong the central vertical plane to receive the ends of said tubes, aniron core slidable within said smaller tube, two non-magnetic screwsthreaded in hubs of said parts to engage opposite end of the iron coreto adjustably position the core in the smaller tube, said shell providedwith an opening to bring out lead wires from said windings whereby saidwindings can be connected to variably tune the main winding according tothe setting of said iron core, and molded nuts to screw one on each ofsaid screws to avoid entry of moisture into said shell and to preventmovement of the screws while in service.

9. In a receiving coil for train communication apparatus, thecombination comprising, a winding mounted on an insulation tube ofrelatively large diameter, a circular shell of two identical parts ofmolded non-magnetic material having joining surfaces falling along thecentral vertical plane and a rim to assemble the parts by screws spacedaround the rim, said shell forming a compartment for housing saidwinding by the ends of the tube fitting into annular grooves molded onein each of said parts, said joining surfaces molded with an annulargroove to receive a gasket for sealing the assembled shell, 2. lugmolded to each of said parts to form two mounting surfaces and an outersurface when the parts are assembled, said outer surface being connectedto said compartment by an opening to bring out lead wires of saidwinding to a terminal box attached to said outer surface, and twoU-shaped metal brackets bolted one to each of said mounting surfaces tomount the receiving coil to brackets with said shell substantially freeof strains.

EDGAR W. BREISCH.

